Upload
britto-samuel
View
900
Download
0
Embed Size (px)
Citation preview
Geiger Muller Counter
AVS College of Arts and Science, Salem
Presented By: Britto Samuel, I Msc Biotechnology,
Department of BiotechnologyAVS College of Arts & Science,
Introduction• The Geiger counter is an instrument used for measuring ionizing radiation
• It detects ionizing radiation such as alpha particles, beta particles and gamma rays using the ionization effect produced in a Geiger–Müller tube
• It is perhaps one of the world's best-known radiation detection instruments
History• The original detection principle was discovered in 1908
• The development of the Geiger-Müller tube in 1928 that the Geiger-Müller counter became a practical instrument.
• It has been very popular due to its robust sensing element and relatively low cost.
Old GM Counter
GM Counter Using for Ukraine Military Purpose
Operating Principle• A Geiger counter consists of a Geiger-Müller tube, the sensing element which detects the radiation, and the processing electronics – Results in Display
• Geiger-Müller tube is filled with an inert gas such as helium, neon, or argon at low pressure, to which a high voltage is applied
• Tube briefly conducts electrical charge when a particle or photon of incident radiation makes the gas conductive by ionization
Operating Principle
Operating Principle• The ionization is considerably amplified within the tube by the Townsend Discharge effect to produce an easily measured detection pulse
• This large pulse from the tube makes the G-M counter cheap to manufacture, as the subsequent electronics is greatly simplified.
• The electronics also generates the high voltage, typically 400–600 volts
Readout 2 Types
Count per second Absorbed dose
Count per second
• The number of ionizing events displayed either as a count rate, commonly "counts per second“
• The counts readout is normally used when alpha or beta particles are being detected
Absorbed dose• More complex to achieve display of radiation dose rate, displayed in a unit such as the sievert
• Normally used for measuring gamma or X-ray dose rates
How it works?
How it works?• Radiation (dark blue) is moving about randomly outside the
detector tube.• Some of the radiation enters the window (gray) at the end of the
tube.• When radiation (dark blue) crash with gas molecules in the tube
(orange), it causes ionization: some of the gas molecules are turned into positive ions (red) and electrons (yellow).
• The positive ions are attracted to the outside of the tube (light blue).
• The electrons are attracted to a metal wire (red) running down the inside of the tube maintained at a high positive voltage.
• Many electrons travel down the wire making a burst of current in a circuit connected to it.
• The electrons make a meter needle deflect and, if a loudspeaker is connected, you can hear a loud click every time particles are detected.
Application• For the detection of alpha and beta particles• To detect radioactive rocks and minerals in the course of mineral prospecting or as a mineral collector
• To check for environmental levels of radioactivity• For Fire and Police first responders to a analysis for making an initial determination of radiation risk.
Thank You
Presented By: Britto Samuel, I Msc Biotechnology,
Department of Biotechnology,AVS College of Arts & Science,